Fluorescent paste has been widely used to manufacture fluorescent films for use in display apparatuses, such as cathode-ray tubes (CRTs) and plasma display panels (PDPs), illuminators, such as fluorescent lamps, X-ray intensifying screens, and luminous substances.
Conventional fluorescent paste contains fluorescent fine particles, a solvent, and a binder resin. Fluorescent paste is applied on a substrate to form a coating and is dried or subjected to additional heat treatment to decompose a binder resin and sinter fluorescent fine particles (see, for example, Patent Document 1) or cure the binder resin (see, for example, Patent Document 2), thus forming a fluorescent film.
[Patent Document 1] Japanese Unexamined Patent Application Publication No. 2001-226669.
[Patent Document 2] U.S. Patent Application Publication No. 2003/0099859.
However, as in a light-emitting diode described in Patent Document 2, the remaining binder resin in a fluorescent film reduces the content rate of a fluorescent substance in the fluorescent film, thus lowering the luminous efficiency.
Furthermore, as in a fluorescent film described in Patent Document 1, when the thermal decomposition of a binder resin and the sintering of fluorescent fine particles are performed after the formation of a coating, although the content rate of a fluorescent substance in the fluorescent film can be high, there are some problems, such as low manufacturing efficiency, poor adhesiveness of the fluorescent film to a substrate, and unavailability of plastics as substrates.